The present invention is directed to a solar still vibrator and more specifically to an electrically operated device adapted to be attached to a solar still for imparting controlled vibrations to the still to facilitate run-off of the condensate droplets formed on the under surface of an inclined sheet.
A conventional solar still is comprised of a container for holding a supply of contaminated or brackish water and a transparent cover extending over the container which permits the rays of the sun to heat and evaporate the water. The cover is usually disposed at an angle relative to the surface of the water so that as the moisture condenses onto the inner surface of the cover, the water droplets will run down the inclined surface of the cover into a suitable collection trough, or the like. Initially, due to surface tension, the droplets forming on the inclined surface tend to remain in one place. Eventually, small adjacent droplets coalesce into a drop of water that runs down the underside of the surface to the collection trough. However, due to the presence of a large number of droplets on the underside of the inclined surface, the efficiency of the solar transmission through the cover is compromised.
In order to improve the efficiency of a solar still, it has been proposed in French Patent No. 2,452,302 to provide a moving element for cleaning the condensing surface of the cover continuously or intermittently and to push the condensate into the collection trough. According to this patent, the moving element could be a manually operated or power driven wiper similar to an automobile windshield wiper. Alternatively, it was proposed in the patent, to remove the droplets of condensate by blowing compressed air over the surface or washing the droplets away by means of a liquid such as pre-collected condensate. The principle drawback with such a system resides in the fact that as the droplets are pushed into adjacent droplets, larger droplets will form to the extent that gravity will overcome the force adhering the droplets to the collection surface and the droplets would fall back into the body of contaminated water, which is being evaporated.